


Slithered Here From Eden

by pureleaf



Category: Kuroshitsuji | Black Butler
Genre: Agni is a missionary, Alternate Universe - Modern Setting, Demon Allergic To All Sacred Things, M/M, Mild Smut, Religious Imagery & Symbolism, apologies for the rushed ending, demonic sebaciel prompts, i was so high while writing this
Language: English
Status: Completed
Published: 2019-07-27
Updated: 2019-07-27
Packaged: 2020-07-23 09:15:48
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,407
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20005897
Author URL: https://archiveofourown.org/users/pureleaf/pseuds/pureleaf
Summary: A missionary shows up on Ciel and Sebastian's doorstep. Ciel is trying to get rid of him just as storm warning sirens go off. He feels he can't send the missionary out into the storm, so he lets him in.





	Slithered Here From Eden

**Author's Note:**

> Hi hello! This lil story is for the tag #demonicsebacielprompts  
> I posted this on tumblr originally, which you can check out @pureleafpoet  
> Thank you for stumbling on this, and if you liked it, please let me know!

In the beginning, there was an echo, carrying sounds like hollow caverns. Ciel would scream to the heavens to prove that he wasn’t the only thing that could occupy a borrowed space. He would fall to his knees and pretend his voice existed within the vacant essence, desperately hoping when it bounced back, the octave would change. So sweet was the song that no one could resist it. For drenched in it was the passionate ache for the moonlight, the hunger for powerful virtue, and the trepidation of desolate spaces. Ciel allowed the darkness to move throughout him. It crawled up his spine and created a home in his heart, like an evil thought from out of nowhere, burying itself in his psyche like a starving parasite looking for a vein. The only difference was the devil and him had a _commensalis_ ; like a golden jackal exiled from its pack, trailing behind a tiger to feed on the remains of its kills. 

In his youth, Ciel was ignited. The cosmos moved in his bloodstream and dripped from his fingers. He would not have been daunted by man or God. When enraptured, the love was like fire and a desperation that he armored like a shield. He adored Sebastian in the way Nero burned Rome, guileless and serene, fiddling a melody amongst the inferno.

But with the weight of the bible, he could break Ciel’s ribs; reach into his dainty chest and tear out the vitality within. Sebastian flicked his tongue around sharp canines, peering eyes gone onyx and frenzied. With a deadly glint, he threw the lithe man against the wall, cupping the back of his head with black talons, razor-edged and famished to rip into a soul, the temptress arching into his touch. The demon had developed a weak spot for the young man, his lips sucking him in like black holes when they bend light. Before their contract, Sebastian wandered amongst the humans, looking up to see the stars racing through the sky to fade quickly into nothingness, and now he implored Ciel wasn’t as fleeting. 

With his tongue and teeth consuming Ciel, he imagined keeping his human to himself. Oh, how easy that would be, but he could never be controlled; like a relentless sea heaving ships into jagged cliff sides. 

“Ah, Seb… _f-fuck_ ,” he groaned into his mouth. 

“Yes, master?” he replied, more breathless than intended. His lips trailed down his lover’s jaw, nipping lightly at his throat, lapping his tongue around the blazing crimson. The young man shuddered, whispering incoherent pleas while sinking to the floor to trace his impatient hands up the demon’s calves. Sebastian tilted his head down to the man on his knees, brushing his nails through silk strands just so he could tug him closer to the tent in his pants. Ciel ran his hands up the inside of his thighs, teasing the bulge through the cloth with hot, panting breaths. When his mouth pressed against him, Sebastian’s true form flickered through like static; shadows leaking through his being to suffocate the room, leaving no space for the divine as the little human wrapped a hand around his shaft. The demon growled, skin decorticating into dripping mercury, more than two eyes piercing with agonizing lust, another groan surging into the unholy room from his tepid mouth. Blackened bones and fiery feathers stretched and released a plume of ash at their feet, a faint glow adorning his body like a halo. The demon was coming undone by the ichor flowing through Ciel, oozing gold and crowning him on a crumbling throne. 

Before Sebastian could incinerate their clothes and bend Ciel over their bed, three loud knocks against the door interrupted the transgression. With a swift wrench, his human guise swathed and reclaimed him, a harrowing sickness enveloping him. 

“Christ, who the hell could that be,” Ciel huffed as he pushed the hair out of his face, wiping his mouth with the sleeve of his shirt. He fixed himself before stepping out of the room, a hollow pit forming in Sebastian’s stomach watching his master leave. Something didn’t feel right. The closer he followed Ciel to the front door, the worse he felt; his breaths coming sharp and slow, pinching his chest as if he actually needed to breathe. He could smell hints of sage and sanctity, fogging his mind like an offing. When the door opened, Sebastian _flinched_. 

“Good afternoon! My name is Agni, and I would love to talk to you about my God and what he has done for me.” 

_Fucking hell._ No wonder Sebastian fell ill, being a demon allergic to all sacred things. 

“Erm, we don’t really have a lot of time to sit and chat,” Ciel tried blocking the view of the man from the demon, but even from a distance Sebastian could see the lightning white hair pulled back from the stranger’s face, a cheerful smile stretching from ear to ear. 

“Oh, I promise you this won’t take long. May I at least pray for you?” Ciel looked Agni over, the man towered in height, alabaster strands tied in a loose bun, the robe he wore was a deep emerald, his silver eyes sparkling regardless of the dark clouds outside. The stranger was truly beautiful, Ciel almost felt bad for shoving him away from the door. 

“I appreciate it, but I already practice a religion. Have a good da-” his gloved hand stopped the door from slamming in his face, a bright grin blessing his features even as he was being banished. 

“Lovely! What religion?” Sebastian cleared his throat and stepped closer to Ciel, wincing as the holier-than-thou caught his glare, flashing his pearly teeth at him, too. “Ah! Hello! I did not see you back there.” 

“Listen, uh, Agni. We were kinda in the middle of one of our, um, _rituals_ , so if you could excuse us…” but just as he was closing the door, a pulsing wail erupted in the city, thunder shook the house violently, and suddenly Ciel felt a surge of guilt. The three men looked at each other uncomfortably until Ciel broke the silence with a long sigh, “Alright, get inside. This is gonna be a nasty storm and I’m not cruel enough to make you walk home in it.” 

“Bless you, sir!” Agni shook his hand enthusiastically as he was let inside. “What are your names?” 

“Ciel. This is Sebastian,” _my demon._

“It’s a pleasure to meet you both. Thank you for allowing me into your home,” he looked around the room before removing his sandals. 

“Of course. I’ll make some tea. How about you relax in the living room, put on the news so we can see updates on this storm,” Ciel said as he started making his way toward the kitchen. Sebastian stopped him in his tracks with a pleading look. 

“I’ll take care of the tea, ma- _Ciel,”_ he corrected. “Go sit down, we will most likely have to move to the basement soon.” Ciel nodded, leading Agni to the couch. Sebastian exhaled and gasped, clutching at his throat the way his young master would during an asthma attack. His vision blurred as he trudged to the stove, trying to snap himself out of it before he gets exorcised. It was the feeling humans experienced in dreams, of being about to hit the ground after falling; the devil pitched forward a bit, caught in his lover’s arms, resulting in an intense head-rush shocking him to breathe. 

“Bastian, what’s wrong? You’ve been acting weird since-” 

“I-I’m sorry, my love. I seem to be susceptible to this righteous stranger,” he choked out a laugh, but Ciel’s worried expression singed his core. 

“I’ll throw him out right now.” He replied, in all seriousness. 

“No, we can’t do that. I’ll be okay, he is just quite… consecrated. I don’t believe he would hurt us,” it came with shivers and wet skin, and the tempest had begun. The house rumbled and shook, branches and leaves smacking against the windows as the downpour roared. It was going to be one long storm.

* * *

“And there shall be a tabernacle for a shadow in the daytime from the heat, and for a place of refuge, and for a covert from storm and from rain.” Agni prayed for the storm to pass while Sebastian cowered at the opposite side of the basement. They had convinced Agni that Sebastian was contagiously ill, and he prayed for his health, too. The demon had to chuckle at that, engrossed in the absolute irony of it all. His eyes ate the darkness, his tongue delved and drank the night, flashing a cheeky tooth at Agni to mess with him as he spoke of his God to the pair. Sebastian lived beyond the grace of God, a monster wandering in the dark. Ciel would dart his eyes at him when he would be caught moving shadows around the basement, flashing his devilish aura in attempts to scare off Agni, but was utterly distracted by an enthralling story. The demon sighed, watching and listening from afar, a stinging possessiveness staining him ravenous. 

“I traveled the desert for days, running low on water and scavenging for food in the wasteland, and I thought for sure I would die,” Agni was captivating. “I begged a high power to save me, and when I felt I was doomed, I pleaded to make my death quick. Of course, I am here to tell the tale.” Sebastian rolled his eyes. 

“So what did you do?” Ciel asked, interested. 

“As I collapsed in the sand, I looked up toward the sky. I saw vultures swarming, probably preparing for a feast, and then I saw a hand reaching for me,” he paused, reaching a palm toward Ciel, Sebastian suppressed a low growl from escaping. 

“I saw a bright glow, felt a warm embrace, and then everything went black. I woke up in a hospital, not remembering much.” Agni continued to talk about how he believes, wholeheartedly, that it was God that saved him, stealing quiet giggles from Ciel as they talked. Sebastian crept closer, feeling like he could retch at any moment, but needing to be near his Ciel. His uncharacteristic wheezing had enmeshed him in ignominy. _Deserts_ , he thought as he inched closer to the old couch they sat on, _scattered with epitaphs, scripture for the catacombs, hoarders of the crumbs of dust and decay, mortal matter._ With evil trapped in the environs of devotion for his human, like a recently archived butterfly, every shadow greeted him with a kiss that left a cool, lingering feeling where he used to have skin. He watched Ciel with each predatory step, freckles thrown against his face like fresh paint, simpering at his demon when he noticed him coming closer. Not even God could command Ciel Phantomhive. 

“How do you feel about the Devil?” Agni’s face clouded with a sort of fascination, Ciel’s mouth curved into a delicious, shallow grin. Agni relaxed his jaw before speaking.

“I think he is necessary, and should be acknowledged. Satan, a fallen angel, but an angel nonetheless. They say the Devil is a liar, a murderer among men, a torturer of Hell. I say he is just doing his job,” both Ciel and Sebastian’s jaw dropped. “I don’t believe he lies, I don’t believe he kills, and the torture comes from within, from our own shame and sin we drown in. The Devil may have been outcasted, but he is still a son of God.” Sebastian joined them on the cushions, wrapping possessive arms around Ciel’s midriff. If he remained one with him, he could find sanity. His lips as in where love is poured from, as in heaven, as in where most humans go to taste God. So often it was as if they shared a single body. Agni smiled at their affection, offering his palms outstretched to them. 

“I feel tenderness between you, Ciel and Sebastian. Hm, yes, a love so soft and waking. I truly feel delighted to be in your home, and to be allowed to share stories with you. I can feel stories of your own through your eyes, especially you, Sebastian,” he gripped his lover tighter in his arms, a sun sick delirium as Agni’s burnished bronze hands came closer. Sebastian was a raven pretending to be a dove in front of this mortal, _this mortal_ who seemed to accept and cherish a relationship between two men, but a _demon_ and a man. 

“Thank you, Agni. We are a bit more on the private side, but we appreciate your understanding,” Ciel spoke, tracing a thumb on Sebastian’s white knuckles, easing his apprehensive thoughts. 

“Of course. ‘ _We are all infected and impure with sin. When we display our righteous deeds, they are nothing but filthy rags. Like autumn leaves, we wither and fall, and our sins sweep us away like the wind.’_ But I can see spirit flowing through you, and know that whatever sin you may have committed, can be rectified and cleansed,” the couple held back a chuckle. _If only he knew,_ they both thought. That right before he showed up on their doorstep, Ciel was _ravished_ by the Devil himself. But Agni beamed at them, a glorious sight to gaze upon, but his eyes could only handle so much. 

* * *

A myriad of stories, six cups of tea (four belonging to Ciel), and three hours later, the thunder and hail came to a halt. They had returned upstairs, feeling lighter and Sebastian alleviated of the malady. When walking Agni out, the demon reflected on the graciousness that the white-haired man embodied; so objective and welcoming of a nefarious being.   
  
“May the light slice through the dark clouds to open the heavens to shine upon you, and keep you. When all feels trapped in despair, know that there is a way out. I pray prosperity on your household, I sense everlasting bliss upon your love, and I hope when we meet again, someday, you can share your story with me.” How enduring that would be. Ciel pictured endless pages of suffering and destruction, saved by a demon, coated in love and worship like magma. Sebastian could only imagine a single page, empty of all but one word, and that word was _Ciel._ Agni left them with their allegories, leaving breadcrumbs of promise and hope, that when their paths crossed, it would be under the same sky.


End file.
